Interpretive Summary: Starch-based electroactive biomaterials are solid polymer electrolytes utilizing ion mobility as the primary mode of conduction within the polymer matrix. Biological polymers (biopolymers) offer a degree of functionality not available in most synthetic ICPs. Biopolymers are a renewable resource and have a wide range of uses such as biosensors, membranes, and biomedical devices. Agriculture-based electroactive biopolymers could also have an economic advantage over synthetic, petroleum-based products in the future.

Technical Abstract:
Biopolymers have the potential for use as a matrix for applications such as controlled release devices, environmentally sensitive membranes, mimic materials and energetic applications. Renewable resources (such as starch) can be utilized as polymer matrices for electroactive materials that are sensitive to their environment. Natural polymers are generally more environmentally-friendly and biocompatible than existing synthetic products. Thermoplastic starch is naturally insulative; however, the chemical, electrical, and mechanical properties of the biopolymer matrix can be tailored for specific functionality in a continuous process utilizing reactive extrusion. Conductance can be measured in the solid state by a direct-current resistance method. Ion-conducting materials, produced by doping thermoplastic starch and biopolymers with metal halides, have 5 orders of magnitude greater conductance than native materials. There is a correlation between polymer mobility and conductance. Plant or microbial biopolymers with ionic functional groups have shown promise for higher levels of conductance. The conductance approaches the level of synthetic polymer electrolytes.